Composite metal foam

This stuff is pretty amazing. Dr. Afsaneh Rabiei has developed a method to suspend hollow metal spheres in a matrix of metals to create a composite material that is nearly as strong as normal metal, but is lighter and much more compressible.

The example of its benefits mentioned in the video is that a car bumper backed by composite metal foam would, due to the amount of energy the compressing foam would absorb, make a 28mph car crash seem like a 5mph crash to a passenger.

read more about it at the Inhabit article Researcher Creates Strongest Metal Foam Ever.